Water Quality and Organochlorine Pesticides in Fresh Water Bodies in the Lower Volta Basin: A Case Study of Lakes Kasu and Nyafie

Abstract

The study was in two parts. The first part dealt with the determination o f water quality parameters such as pH, temperature, DO, BOD, COD, conductivity, turbidity, suspended solids, dissolved solids and total solids. Others are nutrients and ions such as nitrates, nitrites, phosphates, chlorides, calcium, magnesium, sodium and potassium. The rest were under hardness o f water such as calcium, magnesium and total hardness. Of all these parameters, only the values for turbidity i.e 80.8 NTU (Super-drain), 68.0 NTU (Kasu) and 25.2 NTU (Nyafie), were far beyond the WHO guideline limit o f 5 NTU for drinking water. The second part dealt with the qualitative and quantitative determination of organochlorine pesticides levels in both water and sediment samlpes from lakes Kasu, Nyafie and the “super drain” The chemicals, lindane, hexachlorobenzene (HCB) and 2,4,5- trichlorobenzene (2,4,5-TCB), were found to be present using gas chromatography (GC): The water sample mean for HCB in lake Kasu (11.7ng/L) was greater than that found in lake Nyafie (2.3ng/L). No lindane was detected in any o f the sediment samples. The water sample mean for HCB in lake Nyafie (1.9ng/L) and that for lake Kasu (1.3ng/L) were relatively close. Again, no HCB was found in any o f the sediment samples. In the case of 2,4,5-TCB,its water sample mean value for lake Kasu was a high o f 1114.1ng/L, while that for lake Nyafie was 822.5ng/L. Of all the pesticides detected, only 2,4,5-TCB was present in both water and sediment samples of the two lakes. While the sediment mean value for lake Kasu was 125.1ng/L and that for lake Nyafie was 44.2ng/L. On the whole, the lakes can be said to be polluted and as such unsafe for drinking and recreational purposes as a result of the presence o f the organochlorine pesticides found in them.